Electronic voltage regulator technology for rural electrification

Serdyn, J. J. (2008-03)

Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008.

Thesis

ENGLISH ABSTRACT: This thesis discusses the development of a 5 kVA single phase AC voltage regulator, specifically designed to assist in the reduction of electrification costs in sparsely populated rural areas. The voltage regulator is based on a solid state auto-transformer tap changer, designed to be robust and maintenance free. Electrification cost savings can be realized if the length of the LV network can be extended to reach more households. To accomplish this, a voltage regulator can be installed onto the extended LV feeder at the point where the LV voltage will drop below the minimum valid voltage, thereby boosting the voltage downstream and enabling more customers to be connected. A variety of voltage regulator topologies were investigated to obtain the best topology for the application. The voltage regulator design is discussed in detail with careful attention given to the power loss incurred, surge voltage protection requirements, protection coordination with the existing LV network and the thermal design requirements. An electronic controller based on a digital signal processor together with an appropriate power supply is designed and built. The software to control the voltage regulator is developed, integrated with the hardware and debugged. The complete voltage regulator is evaluated through extensive laboratory testing and field trials are performed to verify the performance of the device.

AFRIKAANSE OPSOMMING: Hierdie tesis bespreek die ontwikkeling van ‘n 5 kVA, enkelfase, wisselstroom spannings reguleerder, spesifiek ontwerp om koste besparings te bewerkstellig in die elektrifisiëring van yl bevolkte landelike gemeenskappe. Die spannings reguleerder se ontwerp is gebaseer op ‘n outo-transformator tap wisselaar met vaste toestand skakelaars, om sodoende robuust en instandhoudings vry te funksioneer. Elektrifisiërings koste besparings is moontlik indien die laag spannings distribusie kabel verleng kan word, om sodoende elektrisiteit aan meer huishoudings te voorsien. Om dit mootlik te maak kan ‘n spannings reguleerder geinstalleer word op die punt waar die kabel spanning onder die minimum toegelate spanning daal. Sodoende word die spanning weer verhoog aan al die huishoudings wat aan die verlengde gedeelte van die kabel verbind is. ‘n Verskeidenheid uiteenlopende spannings reguleerder topologieë is ondersoek om die beste topologie vir die toepassing te identifiseer. Die ontwerp van die spannings reguleerder is baie deeglik bespreek en spesifieke aandag is gegee aan die verliese, spits opwelling spannings beveiliging, sinkronisasie met die huidige laag spannings netwerk se beveiligings meganismes en die termiese ontwerp van die stelsel. ‘n Elektroniese beheerder, gebaseer op ‘n digitale sein verwerker, tesame met ‘n toepaslike kragbron is ontwerp en gebou. Die nodige sagteware om die spannings reguleerder te beheer is ontwikkel, geintegreer met die hardeware en ontfout. Die volledige spannings reguleerder is ontleed deur intensiewe toetse in die laboratorium en toets installasies op laag spannings netwerke, om sodoende die nakoming van die werks verrigting vereistes van die toestel te bevestig.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/4495
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